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C. E. BUELL.

TELEPHONE STATIUN APPARATUS. No. 251,521. Patented Deo. 27.1881.

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(No Model.) 2 Sheets-Sheet 2. C. E. BUBLL. TELEPHONE STATION APPARATUS. No. 251,521. c Patented Deo. 27,1881.

UNITED STATES PATENT OFFICE.

CHARLES E. BUELL, OF NEW HAVEN, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE UNITED STATES TELEPHONE MANUFACTURING COMPANY, OF NEW YORK, N. Y.

TELEPHONE-STATION APPARATUS.

SPECIFICATION forming part of Letters Patent No. 251,521, dated December 27, 1881.

Application filed J une 25, 1881. (No model.)

To all whom it may concern:

Be it known that I, CHARLES E. BUELL, ai citizen of the United States, residing at New Haven,in the countyoi' New Haven and State of Connecticut, have invented certain new and useful Improvements in Telephone-Station Apparatus; and I do hereby declare the following to be afull, clear, and exact description ot' the invention, such as will enable others skilled in ro the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of ret'- erence marked thereon, which form a part of this specification.

x5 This invention relates to means for connecting with a main line a branch circuit, including a telephone or other apparatus, its object being to eii'ect such connection without interrupting the continuity of the main line, and

zo thus to prevent the efticiency of the main line from being impaired by-the failure of a subscriber at a station to disconnect his stationtelephone circuit from the main line after iinishing using his telephone.

In the accompanying drawings, Figure l is a diagram illustrating the mode of arranging a branch telephonecircuit for connection with the main line according to my invention.A Fig. 2 is a diagram illustrating a modification of 3o the invention. Fig. 3 is a View in elevation,

illustrating another modification inclosed in a casing of a transmitter.

Referring to Fig. 1, the letters A and B designate ltelephone-stations on the main line L. 3 5 At each ot the stations a call-bell, C, is arranged permanently in the main line, and a -push-button, D, at each station serves to make and break the main circuittor calling purposes. Between the push-button D and the call-bell l4o at each station a metallic contact-plate, E, is

interposed in the main line; and F is a pivoted metallic switch-lever, the free end of which may be brought into contact with or removed from the plate E, as required. To the pivoted end of the switch F is connected a wire, h, which connects at the other end with one terminal of the secondary coil of the transmitter T, the other terminal of said coil being connected by a wire, h', with the receiving-telephone T, from which another wire, h2, leads in 5o the usual manner, and is connected with a ground-wire, g. The interior of the transmitter may be arranged in any ordinary manner. When a call is received at a station it is only necessary to swing the free end ofthe switch-lei- 5 5 ver into contact with the plate E, when the st' tion-telephone circuit will be connected electrically with thc main line, and the telephones may be used in communication over said main line in the usual manner, and at the. same time the 6o main-line circuit will be complete from end to end, and may be used for other purposes independent of telephonie communication. The switches are normally oii' the contact plates at the stations, and-,it is found in practice that their being placed in or out ot' contact with the contact-plates E does not injurionsly affect the transmission of electrical currents on the main line or interfere with communication between stations on opposite sides of an intermediate 7o station.

In Fig. 2 the letter Iindicates a polarized magnet similar in construction to those used inthe ordinary polarized relay. The coils ot' this magnet are included in the main line at a telephone-station, and the polarized armature K has its pivoted end connected with the main line ou one side of the magnet by means of a short wire, l.. On opposite sides of the armature, near its free end, are arranged stops on m', 8o between which the armature has a limited vibration. From the stop m a wire, n, leads to the secondary coil of the transmitter T, the other devices of the station being as usual, and the telephones connected with aground-wire, g. At a station provided with apparatus as now described the station-telephone circuit may be automatically connected with the main line by the sending of an electrical current fromacentral station in the properdirection,or ot' proper 9o polarity to cause the armature K to move toward the pole N of the magnet, this movement bringing the armature yinto contact with the metallic stop m, closing a circuit from the main line over Ythe wire l, armature K, stop m, wire n, the station-telephones, and wire g to the ground. At the same time the main-line circuit continues unbroken through the coils of magnet I. By simple reversal of current the polarized magnet maybe operated in the usual manner to cause its armature to swing toward the poles S and break contact with the stop m, thus automatically disconnecting the stationtelephone circuit from the main line, which still, as before described, continues unbroken through the coils ot' magnet I. 4

In Fig. 3 the letterO represents thecase of the transmitter, in which is arranged a polarized magnet, I', the polarized armature of which is pivoted at fi to vibrate toward and from the poles of the magnet. From the middle of the armature an arm,p, extends upward and serves as the bell-hammer rod. Immediately below one end of the armature (the S pole in this instance) is arranged a rnetallic stop, q, which is connected by a wire, r, with the secondary circuit ofthe inductioncoil U, the other terminal of this circuit being connected with the ground through the station-telephones, as heretofore described. rlhe station-terminals of the line L are connected with the binding-posts c c', respectively, and these posts are connected by wires w and w with the'coils of the magnet I', so that the main-line circuit is permanently completed through said magnet. From the middle ot' the armature a wire, l', connects with the linecircuit on one side of the magnet. The normal position of 'the armature is as shown in the figure, the armature being out of contact with the metallic stop q. When, now, a current of proper direction is sent over the main line theNpole ofthe armatureis attracted by the adjacent core ofthe magnet and the S pole moves downward and comes in contact with the metallic stop q. A circuit is thus established from the main line over the wire l, the armature, stop 1, the secondary circuit of the induction-coil and thence through the receivingtelephone T to the ground, the station-telcphone circuit being thus connected to the main line without in any manner interrupting the continuity of said main line. The primary circuit of the induction-coil is completed by the rising of the telephone supporting arm y when the receiving-telephone is taken o" the hook y, said arm being formed of metal and making contact When itrises with the metallic stop x, which is electrically connected with one terminal of said primary circuit, the other terminal being connected to a local battery in the usual manner. The arm y is connected in a suitable manner, also, with the local battery through the tension-changing devices of the transmitter.

Having now described my invention and explained the operation thereof, what I claim 1s- 1. Inatelephone-station apparatus, the combination, with a mainline, of a branchV groundline which includes a station-telephone, and a switch arranged to connect said ground-line tov the main line without interrupting the continuity of the said main line, essentially as set forth.

2. Ina telelihone-station apparatus, the combination, with a mainline and abranch groundline which includes a station-telephone, of an automatic switch arranged to be operated by the sending of an electrical current over the main line, and to connect the branch groundline with the main line or disconnect it therefrom Without interrupting the continuity of said main line.

3. In atelephone-station apparatus, the combination, with a mainline and a branch groundline which includes a station-telephone, of an automatic switch arranged to be operated by :the sending of alternately-reversed currents over the main line, and to connect and disconnect the branch ground-line with the main line withoutinterrupting the continuity of the said main line.

In testimony whereof I affix my signature in presence of two witnesses.

W. B. HALE, GEO. W. GoY. 

